This invention is related generally to electronically programmable time of day demand meters and more particularly to apparatus for use in such meters which allows the length of demand intervals for registering the consumption of electrical energy on a mechanical register to be electrically changed.
There are various types of time of day demand metering systems, however, none of these systems are programmable to allow the implementation of structure which provides the capability of electronically changing the length of demand intervals in a demand meter. Typical electromechanical time of day metering systems are disclosed in U.S. Pat. Nos. 2,139,821; 2,246,185; 2,132,256; 548,419; 585,258; 591,195; 593,852; 596,283; 597,958; 710,070; 1,078,206; 2,415,653; 3,683,343 and 2,915,704.
One known prior art system of a programmable time of day system is disclosed in U.S. Pat. No. 4,050,020 to Germer et al and assigned to the assignee of the present invention. This patent is directed toward an electronic time-of-day metering system which is preprogrammed to selectively activate two sets of register dials at predetermined times of the day to register the amount of power consumed during designated peak intervals (eg. high-peak and mid-peak). The present invention is ideally suited for operation with the invention of the U.S. Pat. No. 4,050,020, comprises an imrovement thereof and is incorporated specifically herein as an essential reference. Further, U.S. patent application Ser. No. 724,040, filed Sept. 17, 1976, now U.S. Pat. No. 4,093,997 entitled "Portable Programmer for Time-of-Day Metering Register System" and assigned to the assignee of the present invention discloses a programmer for programming the meter of U.S. Pat. No. 4,050,020 and the present invention. The present invention is is also disclosed in a U.S. patent application entitled, "Time of Day Demand Metering System and Method", to Germer et al, Ser. No. 881,503, filed Feb. 27, 1979.
In a time-of-day demand metering system, the consumption of power is measured and recorded on a demand meter register during demand intervals of a predetermined length. The demand interval length has heretofore been for a fixed length of time (eg. 15, or 30 minutes). In today's market, however, with the escalating costs of generating electrical energy, and with such a wide variety of demand power users (the demand for power during on-peak periods may be for greater and longer periods in some areas than in others) utility companies desire a universal meter which can readily be altered to change the demand interval length without making expensive mechanical or electrical modifications to the meter. Such a meter reduces its manufacturing cost and thus the cost to the utility. Further, purchasing and handling costs become less expensive, since only one type of demand meter need be ordered for use in all of the various geographic locations of varying demand usage.
Therefore, a need exists for a time-of-day demand metering system which provides the capability of readily selecting various lengths of demand intervals without the need for expensive mechanical or electrical modifications to the meter.
It is therefore an object of the invention to provide a time-of-day demand metering system having enhanced operating capabilities.
It is another object of the present invention to provide an improved apparatus for selectively changing the lengths of demand intervals in a time-of-day demand meter which eliminates the need to make expensive mechanical or electrical changes to the meter.
It is a further object of the invention to provide a programmable time-of-day demand meter having means adapted for selecting the desired length of a demand interval.
A still further object is to provide apparatus in a programmable time-of-day demand meter responsive to a program stored therein to selectively control the length of demand intervals as specified by the program and as selectively determined by the apparatus.